Positive Development: Dengue Vaccine



Why is this important

(Image Source: thehindu.com)


Now we come to the indirect health impacts of climate systems. Such as the impacts on mosquito-borne diseases.

This brings us to Dengue.

So why talk about dengue?

Dengue incidence has sky-rocketed in India. Dengue is caused by a virus carried within an Aedes mosquito. The mosquito is infected by the virus when it sucks blood from a person infected with the virus. The mosquito then bites another person continuing the cycle of infection. Mosquitoes like warm, moist climates and breed in pools of water. Infections peak during and after a rainy spell.

What does this have to do with climate change?

Let us look at the two main signs of climate change and see how they impact this disease:

First, temperature. An increase in temperature has several ways of increasing Dengue prevalence: it increases the length of the dengue infectious season, it increases the geographic spread of Dengue, it allows for the virus to reproduce faster within the mosquito, shortens the incubation period and lastly allows for the mosquito to survive better which increases its chances of biting (and infecting) more people. Also, a very hot atmosphere weakens our immune system making us easier prey to the disease.

Next, the alternating flood-drought scenario that comes along with climate change causes water to stagnate (made worse by rubbish clogging drains) forming ideal breeding grounds for mosquitoes. Also, water shortages in cities cause people to store water in containers – this also increases the breeding sites for mosquitoes.

So, while further modelling studies are required to understand precisely by how much dengue will go up in India in the coming decades due to a warming climate, we can safely say: it will go up by a lot.

That’s not a pleasant thought.

What can we do?

First, the news of a vaccine recently released in Mexico is a very positive thing. Perhaps our domestic vaccine manufacturers can also join the race to make a cheap, effective vaccine.

Two, Water management needs to be put on a war footing. India has successfully managed her coal problems and laying out roads faster than predicted. We need to see that happen with water too.

Three, given that Dengue is going to become much more prevalent, we cannot hide from the problem.  Singapore reported 11265 cases of Dengue in 2015. Compare this with the 90040 reported cases in India in 2015 with 200 times the population of Singapore and a much dirtier environment. This suggests rampant under-reporting – a fact confirmed off-the-record by most doctors.

Let us acknowledge there is a problem. Let us consider the possibility that it may get a lot worse. We can then begin to deal with it.


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